Automatic slide projector



5, 1969 T. F. AASEN ET AL 4 3,459,474

AUTOMATIC SLIDE PROJECTOR Filed Dec. 23, 1966 14 Sheets-Sheet 1 AS my 797 /67 Om b a WWW Aug. 5, 1969 T. F. AASEN ET AL 3,459,474

AUTOMATIC SLIDE PROJECTOR l4 Sheets-Sheet 2 Filed Dec. 23, 1966 1969 T. F. AASEQN ET AL 3,459,474

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AUTOMATIC SLIDE PROJECTOR Filed Dec. 23, 1966 14 Sheets-Sheet 5 Aug. 5, 1969 T. F. AASEN ET AL 5 AUTOMATIC SLIDE PROJECTOR Filed Dec. 23. 1966 14 Sheets-$heet 6 JOSEPH ff- \SCl/LESSEL.

Aug. 5, 1969 T. F. AASEN ET AL 3,459,474

AUTOMATIC SLIDE PROJECTOR I Filed Dec. 23, 1966 14 Sheets-Sheet 7 l N VENTORJ- TOAVAF F. 9/955 M0557 M 666255-32 4 I Aug. 5, 1969 1'. F. AASEN ETAL 3,459,474

AUTOMATIC SLIDE PROJECTOR 14 Sheets-Sheet 8 Filed Dec. 23, 1966 a. iy M W? m W MW W 5W WWE f wc/ Aug. 5, 1969 T. F. AASEN ET AL 3,459,474

AUTOMATIC SLIDE PROJECTOR Filed Dec. 23. 1966 14 Sheets-Sheet 9 Aug. 5, 1969 "r. F. AASEN ET AL AUTOMATIC SLIDE PROJECTOR l4 Sheets-Sheet 10 Filed Dec. 23, 1966 472 Tl l4.

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AUTOMATIC SLIDE PROJECTOR Filed Dec. 23, 1966 14 Sheets-Sheet 12 WH/VVHL l 1' 1 INVENTORS.

4 TO/PULF F fifiJE/V JOSEPH/7f JCAZESSEL Aug. 5, 1969 'r. F. AASEN ET AUTOMATIC SLIDE PROJECTOR 14 Sheets-Sheet 15 Filed Dec. 23, 1966 I JA X m5 M L 4% M f r awn Wm 5 own fp MN Aug. 5, 1969 "r. F. AASEN ET AL 3,459,474

AUTOMATIC SLIDE PROJECTOR Filed Dec. 23, 1966 14 Sheets-Sheet 14 WWWMMJ United States Patent 3,459,474 AUTOMATIC SLIDE PROJECTOR Torulf F. Aasen, Little Neck, Joseph H. Schlessel, Great Neck, and Peter J. Waznys, Richmond Hill, N.Y., assignors to Airequipt Inc., New Rochelle, N.Y., a corporation of New York Filed Dec. 23, 1966, Ser. No. 604,333 Int. Cl. G03b 21/06 US. Cl. 35321 6 Claims ABSTRACT OF THE DISCLOSURE A slide projector having a drive system permitting alternate manual or motor-driven operation with a timer device for automatic slide changing at selected time intervals. A pop-up slide editor is located on the projection axis between the projection lamp and the objective lens for receiving slides for projection. The editor is pivotally mounted to swing into an opening in the projector housing top so that a slide at the viewing position may be manually removed therefrom for editing. An interlock permits the operation of the editor only when a slide is in position for projection and prevents actuation of the projector slide transfer lever when the editor is swung .to the editing position. An automatic lens focusing system is included.

The development of slide projectors from the early manual slide-changing models to the present day completely automatic devices has seen attendant problems arising with each of the advancements. The use of high intensity lamps was accompanied with slide popping, that is, heat expansion and quick bending of the film from the film plane resulting in focusing problems; the use of slide-containing trays to eliminate the need for individual slide handling during projection made ready editing difficult. The introduction of automatic slide changing resulted in difliculties when slide jamming occurred in the machine requiring special designs and modifications of the drive systems.

The embodiment of the present invention is designed to overcome these various problems and provides a com pletely automatic slide projector with improved focusing, editing and slide changer operation.

It is therefore an object of the present invention to provide a slide projector with an improved focusing system.

It is a further object of the present invention to provide such a projector with an automatic focusing system that corrects for slide popping."

It is a further object of the present invention to provide a projector with improved projector lens operation through the incorporation of a lens bed which maintains the projection axis along a given line.

It is a further object of the present invention to provide a projector which permits ready access to the slide being projected for editing purposes.

It is another object of the present invention to provide a projector with an improved drive which will disengage and briefly reverse the changing action in the event of slide jamming in the projector; a slide projector with an improved drive which will permit both manual and automatic operation of the injection lever; and a slide projector which is capable of completely automatic operation.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is "ice shown in the accompanying drawings, forming a part of the specification, wherein:

FIG. 1 is a perspective view of a preferred embodiment of the improved slide projector of the present invention with the associated remote control apparatus;

FIG. 2 is a perspective view of the improved projector with the upper housing cut away to reveal the interior of the projection portion;

FIG. 3 is a perspective view of the forward part of the projection portion of the improved projector taken from the opposite side from the view in FIG. 2;

FIG. 4 is a perspective view of the underside of the improved projector with the lower housing removed;

FIG. 5 is a partial sectional View of the projector looking forward taken through the middle of the projector at the slide receiving slot with the slide injection lever withdrawn;

FIG. 6 is a partial sectional view as in FIG. 5 showing the slide injection lever inserted and the slide in the projecting position;

FIG. 7 is a partial sectional view as in FIG. 6 With the pop-up editor in its extended position;

FIG. 8 is a partial plan view of the improved drive system of the projector of the present invention;

FIG. 9 is a perspective view of the improved yoke member of the present invention;

FIG. 10 is a plan view of the improved drive disconnect clutch of the present invention;

FIG. 11 is a partial sectional view of the disconnect clutch and drive means of the present invention;

FIG. 12 is a partial sectional view of the disconnect clutch shown in FIG. 10;

FIG. 13 is a side view partially in section of the projection lens portion of the projector of the present invention and showing the improved lens bed;

FIG. 14 is a view taken along line 14 in FIG. 13 with the addition of the drive gear mechanism between the objective lens and the focus motor;

FIG. 15 is an enlarged sectional view of part of the focus system drive gear mechanism shown in FIG. 14;

FIG. 16 is a plan view of the forward part of the projection portion of the improved projector with the focus control set on automatic;

FIG. 17 is a plan view as in FIG. 16 showing the arrangement of the parts after the automatic control has advanced the objective lens and through the clutch means the corrector lens arm along with it;

FIG. 18 is a plan view as in FIG. 16 with the focus control set on manual showing the arrangement of the parts after the objective lens and associated clutch mechanism has been advanced while the disconnected corrector lens arm has remained fixed;

FIG. 19 is a view of the forward portion of the rack and pinion arrangement for the improved lens bed with portions broken away for clarity;

FIG. 20 is a side view partially in section of a portion ofthe improved lens bed mounting;

FIG, 21 is a perspective view of the means for transferring the focusing operation between the manual and automatic control;

FIG. 22 is a sectional view of the switch arrangement for transferring operation of the objective lens focusing system between manual and automatic control in the position for automatic control;

FIG. 23 is a view similar to that shown in FIG. 22 with the switch in the manual control position;

FIG. 24 is a sectional view of the clutch mechanism between the objective lens and the cor-rector lens arm as viewed from the rear of the projector;

FIG. 25 is a view partially in section of the slide receiving portion of the projector and the pop-up editor mechanism;

FIG. 26 is a perspective view of the pop-up editor portion of the slide projector;

FIGS. 27 and 28 are views similar to that of FIG. 26 showing the operation of the interlock means with parts broken away for clarity;

FIG. 29 is a view in section of the operating motor drive shaft showing the various drives which operate the cooling fan, the timer mechanism and the slide changing clutch and drive mechanism;

FIGS. 30, 31 and 32 show the operation of the drive mechanism clutch in the engaged position, the disengaged position and when being withdrawn from the engaged position, respectively;

FIG. 33 is a plan view of the improved terminal insulator to be used in the projector of the present invention;

FIG. 34 is a plan view of the improved insulator in its folded position without the electrical components attached;

FIG. 35 is a view along the line 35 in FIG. 34 showing the electrical components attached;

FIG. 36 is a diagrammatic representation of the automatic focusing system;

FIG. 37 is a schematic of the improved operating circuit of the projector of the present invention;

FIG. 38 is a sectional view of the improved timer mechanism showing the face of the timer disc.

The dimensions of the invention as illustrated in the drawings are substantially proportional to the dimensions of the machine as actually built.

The slide projector of the present invention is shown in FIG. 1 and comprises a projection portion 1 and a slide feed and control panel portion 2 contained in an upper (3) and a lower (4) housing. The sockets for the power cord and remote control apparatus are located in the rear of the lower housing 4 and the remote control hand apparatus 5 is provided with focusing '6 and slide changing buttons 7 having forward and reverse controls. The upper housing 3 in the projection portion 1 is designed with a lamp access door 8, an editor door 9, an opening for the projection lens 10, a focus mode knob 11 and a slide receiving slot 12. In the slide feed and control panel portion 2 the upper housing accommodates the slide tray 13, the injection lever 14 and the operating control panel 15.

Considering first the slide fed and control panel portion 2 in FIG. 1 a box-like slide tray '13 is shown in the slide injection position in front of the slide receiving slot 12 and a mounting 16 for a rotary type tray is provided on the housing 3 above the slot -12. The slide injection lever 14 passes through the control panel part 15 of the housing and is fitted on its outer end with a handle 17 for manual operation, The controls on the panel include the following: an on-and-off switch 18 with individual settings for putting on the motor alone or the motor and the lamp together; a two-position manually operated button 19 for single-change forward or reverse operation; a timer dial 20 for setting the time in seconds desired between slide changes during automatic operation; and a level wheel 22 for raising or lowering the projection axis in the vertical plane by adjusting a leveling leg which extends through lower housing 4.

Next, FIG. 2 shows the projector with the upper housing 3 cut away to reveal the interior of the projection portion 1. At the rear is shown the projection lamp 23 with its housing 24 and associated condensing lens system 25. Next to the lamp section at the rear is the lamp cooling fan 26 and the projector motor 27 which drives the lamp cooling fan and operates the automatic slide changing system and the timer device. At the center of this portion in front of the lamp section is the slide accepting slot 12 and the improved pop-up editor assembly 28. Forward of this is the projection or objective lens assembly 29 and the improved automatic focus system 30.

FIG. 3 is a View of the projection lens assembly 29 and the improved auto-focus system 30 from the other side of projector. The auto-focus system 30 comprises the three mirrors 31, 32 and 33, the corrector lens 34 and the photocell detector means 35. The detent cam 36 which operates the spring-loaded switch 37 for transferring the focus operation between manual and automatic control is shown mounted on the focus control knob shaft 38. The circuit arrangement 39 for automatic control is mounted on an insulated board 40 on top of the photocell tunnel 41. The objective lens 42 is located toward the rear with its lens bed bracket 43 having a clutch arm 44 which operates on the corrector lens support arm 45. This arm 45 is positioned in an appropriate clutch bed 46 bonded to a flange on the auto-focus system support bracket 47.

The front leveller leg 48 and carrying handle 49 are shown at the front of the chassis 50 and the timer housing 59 and the solenoid which operates the drive engaging clutch 61 are located at the right of the figure.

FIG. 4 is a view of the underside of the projector with the lower housing removed and shows the improved drive system 51 for slide changing located in the center. The focus motor 52 for moving the objective lens bed 145 when actuated by the manual or automatic focus system 30 is positioned toward the front. The timer control 20 is toward the rear as well as the sockets 53, 54 and 55 for the power cord, remote control apparatus 5 and the projector lamp 23 respectively. The level adjustment leg 48, controlled by the levelling wheel 22 through pinion 56, and the carrying handle 49 are located at the front of the projector. Toward the far side are the reverse drive operating solenoid 57, the drive engaging clutch 61 and a levelling leg 58.

The general operation of the projector is as follows: the power cord 62 and the remote control apparatus 5 are attached and a slide tray 13 is positioned in the projector with its front end adjacent the slide receiving slot 12. The first slide is inserted through the slot by means of the lever 14 and the motor 27 and lamp 23 are turned on. The focus knob 11 is set on Automatic for 20 to 30 seconds and then on Manual. The projected image is properly framed on the viewing screen using the levelling leg 48. The projection lens 42 is adjusted by pressing the focus button 6 on the remote control apparatus until the slide image comes into precise focus on the screen. The focusing knob 11 is then turned to Automatic and a fine focus will be automatically maintained by the improved auto-focusing system 30 during the remainder of the viewing.

The controls provide for slide changing in four different ways. The tray 13 may be advanced and successive slides shown by either hand operating the slide injection lever 14 or by pressing the button 19 at the rear of the control panel 15. This button 19 when pressed down halfway will advance the tray 13 to show the following slide or when pressed down all the way moves the tray 13 in reverse to show the preceding slide. The third method is by pressing the Operate button 7 on the remote control apparatus 5 at the front or the rear thereof which permits the respective selection of a slide following or preceding the one being projected. The slide changing operation may also be automatically controlled by simply setting a desired time interval on the timer dial 20 which has increments of 4, 8, 15 or 30 seconds.

The actual slide changing operation is best seen by reference to FIGS. 5 and 6. In FIG. 5 the slide tray 13 containing the slides 64 in slide holders 63 is positioned adjacent the slide receiving slot 12 with the injection lever 14 withdrawn to a position ready to inject the slide 64. The injection lever 14 may be operated manually or, if desired, by any of the three other motor-driven slide changing means described above. As illustrated, the motor-operated drive means 51, comprising the gear 65 and a drive disc 66, is engaged and has completed half a rev olution. The roller 67 fixed on the periphery of the rotating drive disc 66 acts against the flanges 68 and 69 on a yoke member 70 causing it to reciprocate from right to left. The yoke 70 is mounted on a slide transfer lever 71. During the next half a revolution the drive disc 66 will draw the slide transfer lever 71 and with it the connected injection lever 14 to the left forcing the slide 64 into the slot 12 to the projecting position.

The slide receiving mechanism 72 along the projection axis comprises upper and lower guide means 73 and 74, a slide holding spring 75 and a shutter means 76 fitted with an anchor 77 which is connected by means of a spring 78 to a pusher arm 79 on the end of the transfer lever 71. As the injection lever 14 pushes the slide 64 into the projecting position the pusher arm 79 passes against a tab 80 on the shutter anchor 77 forcing the shutter 76 out of light beam-interrupting position as shown in FIG. 6 to be replaced by the slide 64. When the slide 64 is withdrawn from the projection position an abutment surface 81 on the front of the pusher arm 79 will force the slide 64 back into the slide tray 13 while the spring member 78 draws the shutter 76 back into beam-interrupting position.

If during the projection of any slide it is desirable to remove it from the projector for re-orienting it or more closely examining it, opening of the slide editor door 9 will cause the editor assembly 28 to pop up presenting the projected slide 64 for ready manual removal as shown in FIG. 7.

The various improved features will be described in greater detail under separate headings in the following order:

(1) Drive and Disconnect System (2) Timer (3) Pop-Up Editor (4) Lens Bed (5) Automatic Focus System (6) Control Circuit (7) Simplified Terminal Insulator Cover DRIVE AND DISCONNECT SYSTEM The driving power for the slide changing operation is transmitted from the projector motor 27 over a pulley 82 and an O-ring belt 83 to the driven pulley 84 (FIG. 29). This latter pulley 84 is constantly running when the motor is on. A spring-held plunger 85 in the solenoid 60 keeps the clutch jaw 86 on the drive shaft 87 disengaged from the jaw 88 on the pulley 84 (FIG. 31). When the solenoid is energized the plunger 85 is retracted and the spring 89 moves the clutch jaw into engagement with the jaw 88 on the drive pulley 84 (FIG. 30). This pulley 84 now drives the shaft 87 and the drive worm 90 attached at its other end (FIG. 8).

The drive worm 90 engages the drive gear 65 which has a drive disc 66 mounted above it. The drive disc 66 is driven by the gear 65 through a disconnect clutch arrangement (FIGS. -12) and has fixedly mounted on its periphery the roller 67 which rides the yoke 70. The yoke 70 is connected to the slide transfer lever 71 and each rotation of the disc 66 transports the yoke 70 and the attached transfer lever 71 in and out between the two extremes of their translation.

The yoke 70 arrangement is shown in FIG. 9 and comprises a mounting bracket 91 and'a crossbar 92 having two abutment walls 93 and 94 formed thereon. The wall 93 extending the full width of the crossbar is the out wall and the wall 94 extending half the width of the crossbar is the in wall. The roller 67 operates along the crossbar 92 and during a rotation of the disc 66 the roller 67 follows a circular path with respect to the chassis 50. During the first half revolution the roller 67 will slide along the out wall 93 forcing the transfer lever 71 to translate to the out position. During the second half revolution the roller 67 slides along the in wall 94 forcing the lever 71 to translate to the fully inserted position. A

switch cam 95 on the edge of the drive disc 66 operates a switch leaf 96 at the end of each revolution which breaks the circuit to the drive shaft clutch solenoid 60. The solenoid 60 is de-energized and the plunger 85 under the action of the spring 97 is projected outwardly engaging a cam surface 98 on the clutch jaw 86 (FIG. 32) and withdrawing the jaw 86 from engagement with the jaw 88 on the drive pulley 84. Rotation of the disc 66 is thereby stopped and the roller 67 comes to rest in the position shown in FIG. 8. If it is desired at this point to manually operate the lever 71 before the next driven revolution, the roller 67 and related mechanism will not interfere with the withdrawal of the yoke 70 and attached transfer lever 71. The lever 71 may likewise be reinserted without any interaction with the drive system.

As another feature of the drive system the gear 65 and disc 66 are connected by an improved disconnect clutch 99 which will disengage the slide changing means from the drive gear 65 in the event of jamming of the apparatus by a slide or other obstruction. The disconnect clutch arrangement 99 is best seen in FIG. 10 wherein the rollers 100 are mounted on the face of the drive gear 65 on two roller arms 101. These rollers 100 are tensioned against a drive cam 102 on the underside of the drive disc 66 by tension springs 103. One end of these springs 103 is attached to the roller arm 101 and the other end to a tentensioning bracket 104. The tensioning bracket 104 is connected by an adjustment screw 105 to the gear face 65. Turning of this screw 105 will either increase or decrease the pressure of the rollers 100 against the drive cam 102 and so control the sensitivity of the clutch 99.

During operation if the injection lever 14 hits an obstruction the action of the yoke 70 will be stopped. The particular abutment wall on the yoke 70 being driven at this point will stop the drive roller 67, and with it the disc 66, from rotating. As the gear 65 is driven further by the worm 90 the attached spring-loaded rollers 100 will be forced to rise on the stopped cam faces 106 on the underside of the drive disc 66. The resistance offered by the springs 103 to this ride up action constitutes the clutch force and therefore the resulting pressure on the jammed slide or obstruction. If resistance to this force continues then the rollers 100 will pass over the detent shoulder 107 on the cam 102 and the springs 103 will be stretched to a point maximum force. As the rollers 100 ride along the cam surface 102 they will reach recessed portions 108 just prior to seating in the opposite recess 106. At this point the pressure of the rollers 100 against the receding cam faces 108 acts in a reverse sense causing the cam 102 and the drive disc 66 to rotate for about 30 in the opposite direction from the gear drive 65. This action will reverse the direction of travel of the slide transfer lever 71 causing it to withdraw to release the jamming engagement. The rollers 100 will then seat in the opposite cam recesses 106 and begin the normal drive operation again. If the jamming action recurs or if continued jamming results the slide transfer lever 71 will continue to be withdrawn by the above described roller ride up action until the jammed condition can be relieved.

TIMER An improved timer for completely automatic slide changing is incorporated in the projector and is operated by a timer knob 20 located on the control panel 15. The knob 20 may be set at any of five positions to give automatic slide changing at intervals of either 4, 8, 15 or 30 seconds or oif. The timer knob 20 operates (FIG. 4) a shaft 109 which positions a set of contacts 110. These contacts are connected by means of wires to the timer mechanism 59 located on the opposite side of the projector adjacent the drive motor 27. The timer mechanism 59 is belt-driven from the 3300 rpm. motor 27 as shown in FIG. 29. It comprises four contacts 111, 112, 113, 114 and a common wire 115 which ride on a rotating disc 116. The disc 116 has a number of conductor arms 117 of varying lengths attached to its face as shown in FIG. 38. The principle of operation is as follows:

The contact 111 for 4-second interval operation is positioned closest to the center of the disc 116 and the contacts 112, 113 and 114 for larger interval operation are respectively positioned at greater distances from the center of the disc 116. During a revolution of the disc 116 it will be seen that the 4-second contact 111 will pass over each of the eight conductor arms 117 while the 8-second contact 112 will pass over only four and the -second and -second contacts 113 and 114 will pass over two and one respectively. The disc drive is geared down to a speed of a little over 2 rpm.

The desired slide changing interval is set by the knob 20 on the control panel 15 which will connect the particular interval contact selected through a circuit to the drive clutch solenoid '60. As the timer disc 116 rotates the circuit will be closed each time that the selected contact touches a conductor arm 117; the plunger will be retracted thereby engaging the drive clutch 61 and causing the slide transfer mechanism 71 to operate. At the end of each revolution of operation the drive disc 66 opens relay 96 by means of the cam breaking the circuit. Drive 51 operation then ceases with the slide 64 in the projecting position until the circuit is again made through the timer 59.

POP-UP EDITOR When a slide has been incorrectly inserted in the slide tray so that the image is inverted or upside down or if it is desired for any reason to more closely inspect the slide it becomes desirable to be able to remove the slide from the projector without having to reinsert it in the slide tray and then remove the entire slide tray in order to gain access to the particular slide. An editor feature is therefore provided in the present improved projector whereby the opening of a door in the top of the projection portion will cause the slide to be lifted out of the projecting position and readily accessible for manual removal. An improved assembly is variously shown in the FIGS. 57 and 25-28.

Considering first FIG. 25 which is a side view taken at the slide receiving slot 12, the editor door 9 is shown mounted in the housing 3 above the editor assembly 28. The door 9 is provided with an inner latch assembly 118 which acts against a pin member 119 located on the slide carrier plate 120. The carrier plate assembly is mounted on a support bracket 121 which also mounts an editor interlock mechanism 122. The carrier plate assembly comprises upper and lower slide guide members 73 and 74 and a shutter member 76 which rides in rails 123 mounted on the carrier plate 120.

Turning to FIG. 5 we see the arrangements of the various parts as a slide 64 is about to be transferred from the slide tray 13 to the projection position by an injection lever 14. At this point the carrier plate assembly is locked in position against vertical movement by the locking pins 124 mounted on the support bracket 121; and against horizontal movement by the spring-loaded editor door inner latch 118 and the interlock 122 mounted on the opposite side of the support bracket. The shutter member 76 is positioned to interrupt the passage of the light beam through the optical system. In FIG. 6 the injection lever 14- has inserted a slide 64, mounted in a slide holder 63, into the projection position on the optical axis. The upright pusher arm 79 located at the end of the transfer lever 71, which is attached to the injection lever 14, has an abutting surface 125 which acts against a tab 80 on the anchor piece 77, attached to the shutter 76, forcing the shutter to slide on its rails 123 out of the way of the projection axis.

When it is desired to remove the projected slide 64 for editing the editor door outer latch 126 is depressed and the spring 127 on the inner latch 118 provides an initial pop-open impulse presenting the end of the door beyond the housing for gripping. As the door 9 is slid open, the forward abutment flange 128 on the inner latch 118 contacts the pin 119 on the carrier plate 120 sliding the assembly 28 across the support bracket 121 out of engagement with the locking pins 124. Further sliding causes the carrier plate center pivot 129 to operate the interlock 122, and permits the carrier plate 120 and assembly to pivot upward about the center pivot 129 presenting the slide 64 above the projector housing 3 for manual removal from the guides 73, 74 as shown in FIG. 7.

INTERLOCK OPERATION This unlocking and pivoting operation is best described with reference to FIGS. 2628. As the slide 64 is inserted in the projecting position the end of the transfer lever 71 contacts a ride-up surface 130 on the lower part of the interlock plate 122 raising the plate 122 a slight distance. This raising action lifts the slot 131 in the interlock plate 122 enough to unlock the center pivot pin 129 on the carrier plate 120 (the position of pin 129 is shown in dotted lines in FIG. 28). As the carrier plate assembly 120 slides along the support bracket 121 the pivot pin 129 rides on a cam surface 132 on the interlock plate 122 raising the interlock plate 122 an additional distance and thereby interposing the locking hook 133 on its lower part into a locking slot 134 on the end of the transfer lever 71. The center pivot 129 continues along the extended surface 135 on the interlock plate 122 and passes over the detent 136 striking the end of the cut out guide 137 in the support bracket 121. The abutment of the center pivot 129 against the end of the cut out 137 causes the carrier plate 120 and assembly to pivot upward about this point. The end pivot 138 on the carrier plate 120 meanwhile has ridden along the end guide slot 139 in the support bracket 121 and engages the spring detent 140 at the end of the slot 139 holding the editor in the upward position as shown in FIG. 7. At this point the slide transfer lever 71 may not be withdrawn as it is held in the locked position by the engagement of the locking hook 133 in the locking slot 134.

After the editing has been completed the editor door 9 is pushed toward the closed position. This action causes the rear abutment flange 141 on the inner door latch 118 to engage the pin 119 on the carrier plate assembly 120 which has been resting on a stop extension 142 on the support bracket 121. The end pivot 138 is released from the spring detent 140 and the carrier plate 120 and assembly is pivoted back about the center pivot 129 until the carrier plate stop 143 engages the top of the support bracket 121. Further sliding of the editor door 9 causes the carrier plate 120 to slide on the sup port bracket 121 and its center pivot 129 to ride back past the interlock plate detent 136 and up along the cam surface 132 until the carier plate 120 engages the stop pins 124 at the end of the support bracket 121. The center pivot 129 has ridden to the opposite end of the support bracket cut out 137 permitting the interlock plate 122 to be droped down by the action of the spring 144 thereby unlocking the slide transfer lever 71. The slide 64 is now ready to be changed and normal operation continued. Withdrawal of the transfer lever 71 drops the locking slot 131 in the interlock 122 about the center pivot 129 locking the carrier plate assembly 120 against sliding on the support bracket 121.

THE LENS BED The projection or objective lens bed 145 is shown in FIG. 13 and slides on the projector chassis 50 driven by a rack and pinion, 146 and 147, respectively. If as sometimes happens the teeth 148 of the rack 146 or the pinion 147 are imperfect the rack 146 and connected lens bed 149 may be forced upwardly misaligning the projection axis of the lens 42 and the proper focus axis and thereby distorting focusing. This improper lifting action is eliminated by the use of resilient couplings between the rack 146 and the bed 149.

The improved arrangement shown in detail in FIGS. 19 and 20 includes studs 150 on the rack 146 resiliently coupled to the bed 149 by friction washers 151 to permit the studs 150 to lift independently of the bed 149. In addition the rack 146 is retained on the chassis 50 by spring clips 152 mounted in slots 153. The arms 154 of the spring clips 152 work on inclined portions 155 of the slots 153 to urge the rack 146 downwardly. When the rack 146 is forced up by the improper engagement of the rack and pinion teeth 148 the studs 150 will be raised without lifting the bed 149 and the spring clip arms 154 are compressed to accommodate for this motion. The spring clip arms 154 react by pressing outwardly on the inclined surfaces 155 to urge the rack 146 back down to its normal position and returning it when the lifting force passes. Thus the lens bed 149 at all times remains in sliding contact with the projector chassis 50 maintaining the projection axis of the lens system in its original proper alignment.

AUTOMATIC FOCUS SYSTEM The focusing operation as previously described has two phases-the projector-to-screen focusing and a fine focus adjustment which corrects for slide movement or popping during projection. The control knob 11 located forward on the top of the projector is used to switch between these two phases of operation.

A conceptual diagram of the automatic focusing system is shown in FIG. 36. A beam of light 156 from the projection lamp 23 is focused by a mirror system onto the center of the projected slide 64 at an angle of about 40. The mirror system comprises the front surface mirrors 3 1, 32 and 33. The light beam 156 during is reflections passes through a small lens 34 which is adapted through a clutch means 44-45 to move with the objective lens 42. The reflection of the light beam 156 from the projected slide 64 is picked up by another small lens 157 which focuses it through an infra-red filter F onto a beam splitter arrangement 158. When the light 156 is centered on the beam splitter 158 an equal amount of light is deflected to each side at 90 from the beam direction. Two cadmium selenide cells 159 are placed on opposite sides of the beam splitter 158 so that light deflected from the beam splitter 158 will strike their sensitized surfaces. Under these conditions with the light beam 156 divided so as to fall equally on the two cells 159, the entire system is in a static or null condition. This condition is achieved by first setting the system by knob 11 on Automatic for a brief period before switching to Manual." It will prevail when the slide 64 is then initially focused properly on the projection screen.

If the slide pops, that is, bends quickly, or moves, a corresponding displacement will take place in the reflected light beam 156 moving it off the center of the beam splitter 158. The cell system 159 will become unbalanced and activate an appropriate control circuit 3-9 (shown in FIG. 38) which drives the focus motor 52 to accordingly move the objective lens 42 either forward or backward to reset the proper focal distance between the lens 42 and the slide surface 64. The small corrector lens 34 connected through a clutch 44 moves with the objective lens 42 to refocus the light beam 156 until it again achieves a null position on the beam splitter 158; at this point the proper focal distance between the slide surface 64 and the objective lens 42 is reached and the drive motor 52 action ceases. The distance between the objective lens 42 and the slide surface 64 will again be precisely the same as the original setting.

A preferred structural embodiment of this system is incorporated in the improved projector. As seen in FIG. 4 the system includes a front surface mirror 31, mounted above the lamp housing 24, which reflects a beam of light 156 passing through the slot 160 in the lamp housing 24. The beam 156 is reflected from the mirror 31 through a cut out 161 in the support bracket 121 onto front surface mirror 32 and from there through a corrector lens 34 to a small mirror 33 mounted adjacent the projection axis. This mirror 33 reflects the beam 156 at an angle of about 40 onto the surface of the slide 64 being projected from whence it passes through a pick up lens 157 mounted at the entrance to the detector tunnel 41 to be filtered by an infra-red filter and detected by the photocell system 159 at the rear of the tunnel 41.

The automatic focusing system 30 is brought into operation through the use of the focus control knob 11 mounted on top of the projector. As best seen in FIGS. 2124 the knob 11 and its associated detent cam 36 mounted on a common shaft 38 operate the spring-loaded switch 37 which transfers focus control between the manual and the automatic systems.

Rotation of the control shaft 38' not only switches between control circuits but also engages and disengages a clutch mechanism between the objective lens bed assembly 29 and the corrector lens support 45. The clutch mechanism (shown in-cross-section in FIG. 24) comprises a clutch surface 162 mounted by means of a spring arm 44 on the objective lens bed bracket 43- and operating on the corrector lens support arm 45 which rides in an appropriate clutch bed 46. As seen in FIG. 23 when the knob 11 is rotated to the Manual setting the control shaft 38 is drawn downward by the action of a springloaded pin 163 on a cam surface 164 on support bracket 47. Through the E-ring 165 and washer 166 the shaft 38 presses the lens arm 45 against the clutch bed 46. This holding action permits the clutch surface 162 to slide on the lens arm 45 during adjustment of the position of the objective lens 42 when focusing on the viewing screen. The detent cam 36 meanwhile has caused the center and upper contacts 167 and 168, respectively, to close permitting control of the objective lens drive motor 52 by the manually operated button 6.

When the control knob 11 is rotated to the Automatic position (FIG. 22), the control shaft 38 is lifted by operation of the pin 163 on the cam surface 164 and pressure on the lens arm 45 through the E-ring 165 and washer 166 is released. The detent cam 36 is also rotated permitting the spring-operated switch 37 to close the center and lower contacts 167 and 169 bringing the photocell-operated automatic focusing system 30 into control of the objective lens drive motor 52. If the auto-focus system 30 is in an unbalanced condition the drive motor 52 will operate to re-position the objective lens 42. During this re-positioning the clutch surface 162, connected to and moving with the objective lens bracket 43', will draw the corrector lens arm 45 along with it through frictional gripping and accordingly re-position the corrector lens 34 until it refocuses the light beam 156 and brings about the null condition. At this time the unbalance signal to the focus motor 52 will cease and it and the objective lens drive 170 will cease operation.

The arrangement of the drive system 170 operated by the focusing motor 52 is shown in FIG. 14 and comprises gear system 171 connected to the lens bed 149 through drive pinion 147. The corrector lens 34 is tied in by means of the clutch connection between the lens bed 149 and the lens arm 45. The gear system 171 is shown in detail in FIG. 15 and comprises a driving worm 172 connected to the motor shaft 173 and driving worm wheel 174. Worm wheel 174 rides on an axle 175 and has cut out portions 176 to avoid burrs on drive disc 177. A clutch spring 178 is provided on the opposite side of wheel 174 to disengage the drive mechanism from the focusing pinion 179 when the lens bed 149 reaches the end of its travel on the chassis. When this occurs motion of the gear train 170' from the bed 149 through the rack 146, pinion 147, drive wheel 180, and focusing pinion 179 ceases. The clutch disengages worm wheel 174 from the drive disc 177 so that the motor 52 may continue running without damage.

To summarize the operation then when the projector is first switched on, the focus knob 11 should be set on Automatic for a brief period with a slide in projection position to permit the null point to be achieved by the auto-focus system 30. The knob 11 is then set on Manual and the operator actuates the focus control on the control panel 15 or the remote control 5 so that the objective lens 42 may be driven to properly focus the slide image on the viewing screen. During this operation the objective lens 42 is disconnected by means of the clutch 44-45 from auto-focus system so that the null point is maintained. When the proper focus is achieved a particular distance will exist between the objective lens 42 and the surface of the slide 64. The knob 11 is again turned to Automatic, which action engages the clutch system 44 45 and switches the focus motor operating circuit 39 from the manual to the automatic control through the detent cam 36 and switch 37. Any further change in the distance between the objective lens 42 and the slide surface due, for example, to slide popping will be detected by the autofocus system 30 and the focusing motor 52 will be accordingly driven to reposition the objective lens 42 and with it the clutch-connected corrector lens 34 until a null condition is again achieved. At such point the slide surface will again be precisely the same distance from the objective lens 42 as in the original setting thereby restoring the desired perfect focus.

CONTROL CIRCUIT A preferred control circuit 39 has been designed to provide for control of the various operations of the projector and is shown in FIG. 37.

Firstly, the power switch 18 arrangement is shown in the lower left hand corner in the off" position. As the contact bar 181 is moved to the right by actuation of the switch it closes the first set of contacts 182 to energize a winding 183 to the projector drive motor 27 which operates the motor to drive the cooling fan and other accessories. In the next position, the last set of contacts 184 are closed adding operation of the projection lamp 23 while continuing the fan and accessory drive. A thermal switch is provided in the projection lamp line which will cut off power to the lamp 23 to avoid burning it out if the system should become excessively heated.

Next, the contacts 186 for the remote control apparatus 5 are shown in the upper right hand corner above the manual forward and reverse button 19. The forward and reverse magnets 187 and 189 are shown in the lower right hand corner along with the switches 96 and 188 which control the drive system clutch 61 and the reverse setting release. The former switch 96 is operated by the cam 95 on the drive disc 66 (FIG. 8) and breaks the circuit disengaging the drive clutch 61 after each disc revolution. The latter switch 188 (FlG. 8) is operated by each in and out action of the yoke member 70 and releases a lever actuated by the solenoid 57 (FIG. 4) that reverses the turning of the slide tray drive pinion 190 (FIGS. 5 and 6).

The focus knob switch 37 is shown at the upper center of the schematic with the Automatic operation contact 169 above and the Manual operation contact 168 below the center contact 167.

The two cadmium selenide cells 159 are connected in a bridge circuit 191 at the lower center which derives its power from a separate winding 192 on the projector motor 27. The output arms 193 on the bridge 191 are tied to the control element of a silicon controlled rectifier (SCR) 194 which is connected through a full-wave bridge rectiher 195 into another winding 196 on the drive motor 27.

52 will turn. The small DC focus motor 52 through a reduction gear drive 170 moves the objective lens 42 either forward or backward depending on the motor drive direction. Dynamic braking is used on the focusing drive motor 52 by shunting it with a low value of pure resistance 197 thus causing the motor to stop quickly and cutting down the inductive kickback to the SCR 194.

SIMPLIFIED TERMINAL INSULATING COVER A simple insulating board and cover is provided, as shown in FIGS. 33-35, which consists of a flat piece of fiberboard 200 formed in such a manner that it consists of two operative halves 201 and 202 which may be folded about a center line A. The board 200 is positioned under the electrical components 203 with their terminal wires 204 extending through the small holes 205 in one half 201. When the terminal connections are completed by soldering the wires to the various terminals, the solid half 202 of the board 200 is folded over on the center line A and is locked in place over the terminals by engagement of the two locking tabs 206. FIG. 34 shows the board in its closed configuration without the components and FIG. 35 is a side view with the components in place.

It will be seen then that an improved slide projector has been provided which is capable of completely automatic operation requiring no adjustments or attention from the operator after the initial set-up. It includes such advanced features as a drive system which is capable of interchangeable automatic or manual operation and which will disengage the slide transfer lever from the motordriven means in the event a slide becomes jammed in the machine and in addition momentarily reverses in action of the lever to thus relieve the pressure on the jammed slide preventing damage thereto. The improved focusing system includes a smooth travelling lens bed and an automatically operating fine focus system to correct for slide popping. An improved pop-up editor, timer device, control circuit and terminal insulating board are additional advanced features of equivalent importance disclosed herein.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, we claim:

1. In a slide projector having means for presenting slides to a projecting position the improvement comprising a door in the top of said projector, means for manually moving said door for opening and closing an opening in the top of the projector, pivotally mounted slide holding means at said projection position having a slide entry aperture at one side which is vertically positioned when the holding means is in the projection position, said slide holding means being operatively connected to said door for being pivoted by the door opening movement thereby moving the slide entry aperture contained in said slide holding means to an inclined position at the opening in the projector top exposed by the door opening and permitting removal and replacement of slides in the slide holding means through the said aperture and the projector top opening.

2. The projector as claimed in claim 1 in which said door comprises a flat plate and the means for mounting said door comprises means for slidably mounting the door for movement in its own plane.

3. In a slide projector having means for presenting the slide to the projecting position the improvement comprising a support member, a slide holding means mounted on said support member, interlock means mounted on said support member, a guide slot in said support member, a pivot on said slide holding means riding in said slot in said support member, slide presenting means which operate said interlock member, a door, means connecting 

